References of "Weber, Georges"
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See detailLa peinture murale à Liège au XVIe siècle : analyse technologique d'une peinture de la cathédrale Saint-Paul de LIège
Oger, Cécile ULiege; Denoël, Sophie; Strivay, David ULiege et al

in Denoël, Sophie (Ed.) Les peintures murales. Les techniques (2008)

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See detailArchaeometry at the Centre Européen d’Archéométrie-Université de Liège
Calvo Del Castillo, Helena ULiege; Mathis, François ULiege; Garcia Moreno, Renata et al

Conference (2008)

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See detailApplication of PIXE and PIGE under variable ion beam incident angle to several fields of archaeometry
Weber, Georges ULiege; Martinot, L.; Strivay, David ULiege et al

in X-Ray Spectrometry [=XRS] (2005), 34(4, JUL-AUG), 297-300

For several years, the specific features of PIXE and PIGE have made them very attractive in the field of archaeometry. Among them, non-destructivity is one of the most important. The possibility of ... [more ▼]

For several years, the specific features of PIXE and PIGE have made them very attractive in the field of archaeometry. Among them, non-destructivity is one of the most important. The possibility of working under atmospheric pressure is also important because of the very different shapes and sizes of the artefacts concerned. However, these ion beam techniques suffer from the same disadvantage: the information coming from x-rays or),brays produced at different places along the charged particle path is integrated. That prevents one from taking into account the possible element concentration gradients due to multilayered systems or diffusion processes. This paper presents several applications of PIXE and PIGE applied under variable ion beam incident angle. PIGE has been mainly used for studying ancient glass items or glass windows in order to detect or evaluate the glass corrosion process. The examples given for PIGE deal with Roman and Merovingian glass objects and cathedral glass windows and PIXE applications concern studies for resolving the multilayered structure of easel paintings. The set-up allowing one to perform the measurements should be very stable, the rotation axis should pass through the beam axis and the detector should follow the sample movement. Copyright (c) 2005 John Wiley [less ▲]

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See detailRepetitive transcranial magnetic stimulation improves open field locomotor recovery after low but not high thoracic spinal cord compression-injury in adult rats
Poirrier, Anne-Lise ULiege; Nyssen, Yves; Scholtes, Félix ULiege et al

in Journal of Neuroscience Research (2004), 75(2), 253-261

Electromagnetic fields are able to promote axonal regeneration in vitro and in vivo. Repetitive transcranial magnetic stimulation (rTMS) is used routinely in neuropsychiatric conditions and as an ... [more ▼]

Electromagnetic fields are able to promote axonal regeneration in vitro and in vivo. Repetitive transcranial magnetic stimulation (rTMS) is used routinely in neuropsychiatric conditions and as an atraumatic method to activate descending motor pathways. After spinal cord injury, these pathways are disconnected from the spinal locomotor generator, resulting in most of the functional deficit. We have applied daily 10 Hz rTMS for 8 weeks immediately after an incomplete high (T4-5; n = 5) or low (T10-11; n = 6) thoracic closed spinal cord compression -injury in adult rats, using 6 high- and 6 low-lesioned non-stimulated animals as controls. Functional recovery of hindlimbs was assessed using the BBB locomotor rating scale. In the control group, the BBB score was significantly better from the 7th week post-injury in animals lesioned at T4-5 compared to those lesioned at T10-11. rTMS significantly improved locomotor recovery in T10-11-injured rats, but not in rats with a high thoracic injury. In rTMS-treated rats, there was significant positive correlation between final BBB score and grey matter density of serotonergic fibres in the spinal segment just caudal to the lesion. We propose that low thoracic lesions produce a greater functional deficit because they interfere with the locomotor centre and that rTMS is beneficial in such lesions because it activates this central pattern generator, presumably via descending serotonin pathways. The benefits of rTMS shown here suggest strongly that this non-invasive intervention strategy merits consideration for clinical trials in human paraplegics with low spinal cord lesions. (C) 2003 Wiley-Liss, Inc. [less ▲]

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See detailSerum selenium in lymphoma.
Beguin, Yves ULiege; Weber, Georges ULiege

in Journal of Clinical Oncology (2004), 22(16), 34293430

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See detailComplexation of uranyl ions by polypyrrole doped by sulfonated and phosphonated polyethyleneimine
Leroy, D.; Martinot, Lucien; Mignonsin, P. et al

in Journal of Applied Polymer Science (2003), 88(2), 352-359

Branched polyethyleneimine (PEI) was sulfonated by reaction with chloropropanesulfonylchloride and phosphonated by reaction with phosphorous acid and formaldehyde. The accordingly formed polyanions were ... [more ▼]

Branched polyethyleneimine (PEI) was sulfonated by reaction with chloropropanesulfonylchloride and phosphonated by reaction with phosphorous acid and formaldehyde. The accordingly formed polyanions were used as doping agents for polypyrrole (PPy). The amount of doping polyanions into thin films of PPy was measured by Rutherford back-scattering. These films were tested for their capacity to extract uranyl ions from liquid wastes of low level activity. The uranium content was determined by neutron activation analysis, autoradiography, and gravimetry of uranium oxide after calcination. The resistance against static and dynamic leachings was also estimated. [less ▲]

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See detailUnequal Lovers at the laboratory. Non-destructive analyses of a sixteenth century Netherlandish painting
Oger, Cécile ULiege; Allart, Dominique ULiege; Fraiture, Pascale et al

in Townsend, Joyce; Eremin, Katherine; Adriaens, Annemie (Eds.) Conservation Science 2002. Papers from the Conference held in Edinburgh, Scotland 22-24 May 2002 (2003)

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See detailNon destructive analysis of a 16th manuscript from the Gospel Book of Robert Quercentius
Denoël, Sophie; Weber, Georges ULiege; Allart, Dominique ULiege et al

in Townsend, Joyce; Eremin, Katherine; Adriaens, Annemie (Eds.) Conservation Science 2002. Papers from the Conference held in Edinburgh, Scotland 22-24 May 2002 (2003)

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See detailArchéométrie et orfèvrerie. À propos de l'expertise d'argenteries liégeoises
George, Philippe ULiege; Weber, Georges ULiege; Martinot Lucien

in Dumortier, Jean-Louis; George, Philippe (Eds.) Regards sur le XVIIe siècle. Feuillets de la Cathédrale de Liège (2003)

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See detailStudy of color centers induced by PIXE irradiation
Absil, J.; Garnir, Henri-Pierre ULiege; Strivay, David ULiege et al

in Nuclear Instruments & Methods in Physics Research. Section B, Beam Interactions with Materials and Atoms (2002), 198(1-2), 90-97

The particle induced X-ray emission method is perfectly adapted to the study, by external beam, of art objects (like paintings) and allows non-destructive analysis of the atomic composition of the target ... [more ▼]

The particle induced X-ray emission method is perfectly adapted to the study, by external beam, of art objects (like paintings) and allows non-destructive analysis of the atomic composition of the target. However, a strange phenomenon occurs during irradiation on some pigments: dark brownish stains appear, and this could be due to the formation of color centers. In fact, these darkening spots progressively fade out and disappear after a few weeks. Heat and UV light accelerate the decreasing process. The aim of this study is to understand the physical processes of the stain creation and to find a way to make stains disappear, avoiding any damage for the painting. (C) 2002 Elsevier Science B.V. All rights reserved. [less ▲]

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See detailAn empirical formula for L line X-ray production cross-section of elements from Ag to U for protons below 3.5 MeV
Strivay, David ULiege; Weber, Georges ULiege

in Nuclear Instruments & Methods in Physics Research. Section B, Beam Interactions with Materials and Atoms (2002), 190

When computing element concentration from proton induced X-ray emission analysis, an important parameter is the X-ray production cross-section. There have been numerous experimental and theoretical works ... [more ▼]

When computing element concentration from proton induced X-ray emission analysis, an important parameter is the X-ray production cross-section. There have been numerous experimental and theoretical works in this field. Nonetheless, although there is a simple analytical formula to compute K X-ray cross-sections, there is no such ones for the L lines. We present here analytical formulas for the cross-section of the three main X-ray lines L-alpha L-beta and L-gamma based on experimental data. So far, nearly 3000 values of cross-sections for elements from Ag to U and proton energy ranging from 0.5 to 3.5 MeV have been collected from various references. This experimental data set has been fitted for each Xray line with an exponential function depending on the proton energy and on the element atomic number. These fitted values have then been compared to the experimental data and with theoretical values obtained by the ECPSSR theory and Coster-Kronig fluorescence yields. (C) 2002 Elsevier Science B.V. All rights reserved. [less ▲]

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See detailUse of PIXE-PIGE under variable incident angle for ancient glass corrosion measurements
Weber, Georges ULiege; Strivay, David ULiege; Martinot, Lucien et al

in Nuclear Instruments & Methods in Physics Research. Section B, Beam Interactions with Materials and Atoms (2002), 189

Although glass is usually considered as a very stable archaeological material, it can undergo severe degradation. Soda-lime glass, the most common glass throughout ancient times, is particularly sensitive ... [more ▼]

Although glass is usually considered as a very stable archaeological material, it can undergo severe degradation. Soda-lime glass, the most common glass throughout ancient times, is particularly sensitive to this problem. The glass surface absorbs moisture from its environment and the contact with CO2 causes Na2O and NaOH to convert to Na2CO3, which is extremely hygroscopic. The subsequent unstable glass layer can be leached out and causes decomposition of the glass. The non-destructive PIGE-PIXE method of investigation allows detection of this phenomenon even if no visible effect appears. The variable incident angle method is able to discern the depth of the degradation. One aim of such studies is the possible dating or at least fake detecting of archaeological materials, Furthermore, even objects of large size can be investigated with the atmospheric PIGE-PIXE Set-LIP, Some examples of measurements on ancient glass are given. (C) 2002 Elsevier Science B.V. All rights reserved. [less ▲]

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See detailPIXE-identification of pigments used in old masters paintings : Black chalk used as a pigment in an oil painting attributed to Lambert Lombard (Liège 1506-1566)
Oger, Cécile ULiege; Allart, Dominique ULiege; Weber, Georges ULiege

in Proceedings of Art 2002 7th International Conference on "Non-destructive Testing and Microanalysis for the Diagnostics and Conservation of the Cultural and Environmental Heritage" (2002)

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See detailRBS Thickness Analysis of Multilayer Mo/Si Thin Films Deposited by RF Magnetron Sputtering
Strivay, David ULiege; Fleury-Frenette, Karl ULiege; Weber, Georges ULiege et al

Poster (2001, July)

Molybdenum and silicon multilayer systems exhibit particularly high reflectivities in the 1-30 nm EUV spectral range for nearnormal incidence operation. They have found applications in astronomy to study ... [more ▼]

Molybdenum and silicon multilayer systems exhibit particularly high reflectivities in the 1-30 nm EUV spectral range for nearnormal incidence operation. They have found applications in astronomy to study the solar corona and could eventually be used as optical components for EUV projection lithography. To attain high reflectivity values, one must rely on effective designs for the superlattice as well as on an accurate metrology system to determine the thickness of each individual layer. These Mo/Si multilayers were deposited at room temperature on polyimide substrate using RF magnetron sputtering in a 5X10-3 mbar Ar atmosphere at constant power of 1.5 W/cm2. We will present here the results of thickness multilayer determination by means of normal and grazing angle RBS analysis as well as the limits of the method for this kind of material. [less ▲]

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See detailControlled exchange of metallic cations by polypyrrole-based resins
Jérôme, Christine ULiege; Martinot, Lucien; Strivay, David ULiege et al

in Synthetic Metals (2001), 118(1-3), 45-55

Binding and release of various cations by polarization of polypyrrole based exchange-resins has been studied. The reversibility of the process has been investigated by electrochemical and nuclear ... [more ▼]

Binding and release of various cations by polarization of polypyrrole based exchange-resins has been studied. The reversibility of the process has been investigated by electrochemical and nuclear techniques. It clearly depends on both the exchanged-cation and the sulfonated doping-ion. The selectivity of the process has also been analyzed by binding experiments from a mixture of two cations. [less ▲]

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See detailArchéométrie et orfèvrerie mosane : émaux du Musée Curtius sous l’œil du cyclotron
George, Philippe ULiege; Weber, Georges ULiege; Martinot Lucien et al

in Bulletin de l'Institut Historique Liégeois (2001)

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See detailA magnetic and conversion electron Mossbauer spectral study of amorphous Dy20Fe80-yCoy thin films
Fleury-Frenette, Karl ULiege; Delwiche, Jacques ULiege; Grandjean, Fernande ULiege et al

in IEEE Transactions on Magnetics (2001), 37(4), 2311-2314

Amorphous thin films of Dy20Fe80-yCoy, with 0 < y < 20 and of ca. 40 nm thickness, have been prepared by sputtering on polyimide substrates. The 295 K conversion electron Mossbauer spectra (CEMS) of these ... [more ▼]

Amorphous thin films of Dy20Fe80-yCoy, with 0 < y < 20 and of ca. 40 nm thickness, have been prepared by sputtering on polyimide substrates. The 295 K conversion electron Mossbauer spectra (CEMS) of these films consist of broadened sextets which have been analyzed with a distribution of hyperfine fields in which the iron moments are oriented perpendicular to the plane of the film, an orientation which is in agreement with the perpendicular magnetic anisotropy observed herein at 295 K by vibrating sample magnetrometry. The average hyperfine field and isomer shift increase linearly with increasing Co content. Both increases arise from an increase in the electron occupation of the 3d states as the cobalt content increases. [less ▲]

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See detailLa clé de saint Hubert, palladium de la cité épiscopale
George, Philippe ULiege; Weber, Georges ULiege; Martinot, Lucien

in Liège. Autour de l'an mil, la naissance d'une principauté (Xe-XIIe siècle) (2000)

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See detailCharacteristics of the iron moment in Dy-Fe and Dy-FeCo amorphous alloys studied by X-ray magnetic circular dichroism
Fleury-Frenette, Karl ULiege; Dhesi, S. S.; van der Laan, G. et al

in Journal of Magnetism & Magnetic Materials (2000), 220(1), 45-51

The local magnetic moment of Fe in Dy-Fe and Dy-FeCo amorphous alloys has been studied using X-ray absorption spectroscopy and X-ray magnetic circular dichroism (XMCD). The Fe orbital and spin magnetic ... [more ▼]

The local magnetic moment of Fe in Dy-Fe and Dy-FeCo amorphous alloys has been studied using X-ray absorption spectroscopy and X-ray magnetic circular dichroism (XMCD). The Fe orbital and spin magnetic moments have been obtained for a range of alloy compositions by applying the sum rules to the XMCD spectra. The room temperature variations of the average components of the Fe moments as a function of Dy concentration and with the substitution of Fe by Co have been determined. A sharp reversal of the total magnetic moment was found at 28 +/- 1 at% Dy for both alloys. (C) 2000 Elsevier Science B.V. All rights reserved. [less ▲]

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